Nearly 300 billion food and beverage containers, bottles and preforms are manufactured worldwide each calendar year. These containers are primarily produced from aluminum but may also be produced from other materials such as steel and other alloys. The material consumed in the production of each container becomes a primary cost of manufacturing. It is common that the material cost comprises more than 30% of total manufacturing cost of each container. Material cost(s) often fluctuate due to market prices resulting in significant changes to profitability for all container manufacturers. The material consumption or the efficiency of material utilization is critical to total product quality performance and realized cost of manufacture. The average container weight of existing art has reached a plateau since 2007, with only 2-5% weight reductions on average being achieved. Prevailing art has reached physical limitations of weight reduction while adhering to the required field container structural performance metrics.
Light-weight metal containers, including metal food or beverage containers and bottle preforms are manufactured in an ironing press or metal forming process resulting in an elongated volumetric cylinder of a shaped metallic container body, preform or bottle or metallic hollow body. The apparatus being generally known in the art as “bodymakers” or “wall ironers” have been traditionally utilized to form these metallic cylinders. Specifically, such metal containers are formed from a base material thickness or coiled sheet. Such containers typically consist of an ironed, or reduced contoured wall which forms a thinwall cylinder, and a contoured base or bottom defined as a “dome profile.” The formation of the dome profile results in a shaped geometric contour formed in a domer mechanism during the completion of the machine stroke. The base profile geometries are formed at the end of a single machine stroke resulting in an individual container being produced with each full stroke of the bodymaker. The domer mechanism utilizes known tooling art commonly entitled as “inner domer die” i.e., “domer post” and the “outer domer die” or i.e., “clamp ring,” to form the base profile geometries. These tools are used to contour form the base profile geometries in standard base formations for the industry.
In general, traditional base profiles utilized in the art consist of a contoured geometric profile shape which is often referred to as a “dolphin nose” contour forming the base profile of the container, and is primarily used to provide the subject container “stackability.” As used herein, the term stackability generally refers to the aspect of fitment with the container base and the container lid as a container may be stacked upon another—such that they may be stored on store shelves or presented within the beverage and food markets as stacked items.
The geometric contour of the base profile is most often divided into two primary shaped regions of an outer base profile and an inner base profile. These contour profiles are normally bisected by the base nose or otherwise defined as the stand diameter. The base nose diameter primarily defines the stackability and is commonly known in the art as the “stand diameter.” Common industry stand diameters are sized as 200, 202, 204, 206, 209 and 300 and the like. For example, a 200 stand diameter correlates to a 2″ base profile. These base sizes are commonly sized by 1/16″ of an inch correlated increments, such that 202 is 2- 2/16 or 2⅛″ base diameter. Correspondingly, 206 equals 2 6/16″ or 2⅜″ and 300 equal 3.00″. These common industry standards define the amount of diametral material to be consumed in the inner base dome profile formation by the analogous size. It should be noted that the novel dome geometries can be formed and applied to any commercial base size.
Traditional metal containers provide an inner base contour consisting of these industry standard diametral sizes producing specific geometric profiles for each correlated base size. The inner contour originates from the stand diameter with an inwardly protruding domed contour of convex shape culminating in a crowned spheroidal shaped radial contour. This domed contour is most commonly comprised of distinct combinations of bi-radial segments and symmetrical radial contours, or a centrally formed singular spheroidal shape commonly referred to as the “inner dome” profile. Traditional dome profiles also typically standardize specific dome depth of inwardly formed protrusion, normally between about 0.37-0.50 inches.
One major limitation of these traditional dome profile designs is that they require a minimum depth of the domed structure to produce adequate strength required to fulfill the minimum internal pressure resistance strength of approximately 70-100 psi (pounds per square inch). Naturally, container minimum internal pressure resistance strength may vary by specific product requirements. The dome profile's performance strength directly correlates to increasing the internal pressure resistance as the dome depth is increased. Subsequently, a corresponding minimum dome depth is required to fulfill industry standard quality performance metrics for each dome design size. Each dome profile family of base design performance is correlated to the minimum depth of the inner dome formation resulting in a specific minimum amount of material consumed. Consequently, traditional dome profiles known in the art are severely constrained as they require a minimum depth that ultimately limits the material savings threshold potential dictated by the performance metrics. Congruently, increasing the material consumption of metal volume absorbed in the dome profile geometry is invariably a direct result of an increased dome depth. Accordingly, it will be shown the novel invention included herein resolves both problems of increased material consumption, and base profile dome strength performance constraints.
The foregoing problems regarding dome profile design and manufacturing may represent a long-felt need for an effective—and economical—solution to the same. While implementing elements may have been available, actual attempts to meet this need may have been lacking to some degree. This may have been due to a failure of those having ordinary skill in the art to fully appreciate or understand the nature of the problems and challenges involved. As a result of this lack of understanding, attempts to meet these long-felt needs may have failed to effectively solve one or more of the problems or challenges here identified. These attempts may even have led away from the technical directions taken by the present inventive technology and may even result in the achievements of the present inventive technology being considered, to some degree, an unexpected result of the approach taken by some in the field.
As will be discussed in more detail below, the current inventive technology overcomes the limitations of traditional dome profile designs and manufacturing methods. In particular, embodiments disclosed herein demonstrate a novel dome profile structure resulting in decreased material consumption and volume, with increased strength through unique geometric formations improving resistance to failure, all while maintaining ease of manufacture, resulting in substantial container weight savings. The unique geometric features result in a base profile realizing significant material savings from the disclosures herein.